Compound thermometer



June 15, 1926. 1,589,294 r q J. M. FUSCA COMPOUND THERMOMETER Fil edNov. 29. 1924 Illl lllll llllll ll gvvuanto'n J/Zihsea Patented June 15,1926.

JOSEPH ivnrnscA, or 'rARENTUM, PENNSYLVANIA;

COMPOUND THERMOMETER.

Application filed November 29, 1924. Serial No. 752,912.

This invention relates to thermometers and more particularly to acompound thermometer for the purpose of determining differences intemperature between two elements or between two portions of the sameelement.

A further object of the invention is to provide a device of thischaracter which in addition to recording the differences in temperaturebetween two given points as set forth above, normally indicates the truetem-' perature in the manner of an ordinary thermometer.

A further object of the invention is to provide a device of thischaracter which is adjustable so that accurate readings may be obtainedand the telltale column of fluids may be adjusted before making the testso that it accurately aligns with a selected graduation of thethermometer sections.

These and other objects I attain by the structure shown in theaccompanying drawings, wherein for the purpose of illustration 7 isshown a preferred embodiment of my invention and wherein The figure is afront elevation of a thermometer constructed in accordance with myinvention, parts of the device being shown in section.

Referring now more particularly to the drawings, the instrument consistsessentiaL ly of a bulb 10 from opposite sides of which extend a pair ofcapillary tubes 11, the free ends of which communicate with bulbs 12. Inthe bulb 10 is arranged a readily expansible liquid of such characterthat it will be readily discernible through the walls of the tube. Inthe bulbs 12, there is likewise an expansible fluid preferably in theform of a gas, as air, although any fluid may be employed as willhereinafter be rendered obvious. It will be seen that the fluid withinthe bulb 10 will expand in response to heat and be forced into the boresof the capillary tubes 11. If the temperature to which the bulbs 12 aresubjectedare equal the columns 11 of fluid in the tubes 11 will balanceand be of equal length. If, however, the bulbs 12 are subjected tounequal temperatures, the columns will be unbalanced due to the factthat one of the bulbs will subject its associated column to a greaterpressure than the other bulb, with the result that the columns willshift until the pressure atopposite sides is equalized.

At the point of connection of each capillary tube 11 with its associatedbulb 12 an elastic section 13 is preferably provided so that bymanipulation of these sections, pressure can be placed against thecolumn 11 of the associatedtube to force the same into alignment with agiven graduation of the tube or as will hereinafter appear of a frame ofwhich the tube is carried. In addition, the bulb 10 is preferablyprovided with a third or inlet tube 14 through which additional fluidmay be introduced to refill the bulb 10 or through which static pressuremay be introduced to force the contents of the bulb into the capillatubes 11. a

A frame 15 is provided f brthe thermometer structure having portions 16.through which are directed threaded'elements 17 for coaction with theelastic sections 13 of the tubes 11 with their bulbs 12. By forcingthese screws into or out of engagement with the elastic walls of thisconnection, the height of the associated column 11 may be regulated asabove described. The frame has additionally a cutout section 18 forminglegs 19 in which the bulbs 12 are supported, this cutout portionseparating these legs so that they are not thermally connected to anyappreciable extent. This frame is provided with a series of graduations20, one for each tube 11.

In the operation of the device, when the sensitive endsv are applied tothe body of a patient, if there is any difference in temperature betweenthe points of contact, there will be a difference in expansion of thegases enclosed in the bulbs 12 with the result that there will be adifference in the levels of the liquid columns 11 thus indicating notonly that there is a difference in temperature but what this differenceof temperature is and at which point the temperature is the highest.This construction renders the device particularly adaptable for securingthe correct location of abscesses and the like which produce a locallyfevered condition in the body of the patient.

While I have above described a particular construction which ispreferred by me, it will be understood that this structure -is capableof a considerable range of change and modification. For example, whiletwo tubes are shown, as many of these tubes may be employed as isdesirable and the adjusting mechanism as represented by the flexibleconnection and adjustable screw may be omitted. Certain other changesbeing possible Without in any manner departing from the spirit of myinvention, I accordingly do not limit myself to such specific structureexcept as hereinafter claimed.

I claim 2- 1. In a thermometer of the type described, a bulb containingan expansible liquid, a pair of capillary tubes, each communicating withthe bulb at one end and having at their opposite end bulbs containing anexpansible fluid the tubes adjacent the last named ends thereof havingan elastic section and means adjustably bearing against such elasticsections to thereby increase or decrease the static pressure Within thelast named ends of the tubes.

2. In athermometer of the type described, a bulb containing anexpansible liquid, a pair of capillary tubes, each communicating Withthe bulb at one end and having at their 0pposite end bulbs containing anexpansible fluid and an inlet tube communicating With the first namedbulb and provided at its free end With a sealing cap.

In testimony whereof I hereunto aflix my 25 signature.

JOSEPH M. FUSCA.

